This carbon nanotube, imaged by a transmission electron microscope, can act as a radio.

Building a Nano RadioA radio receiver made from a carbon nanotube could be used to wirelessly transmit data from ultrasmall sensors

Source: “Nanotube Radio”Alex Zettl et al.Nano Letters 7: 3508-3511

Results: Researchers at Lawrence Berkeley National Laboratory in California have modified a carbon nanotube so that it performs the functions of a radio, even tuning in the entire FM radio band.

Why it matters: Radios are used in everything from cell phones to nodes in sensor networks, and like other electronics, they are shrinking in size. A nanoscale radio could someday find its way into portable electronics such as cell phones. The researchers also suspect that with its small size, the radio could be inserted into a biological cell to transmit information collected by tiny sensors that detect molecular processes.

Methods: The researchers grew the carbon nanotube on a tungsten surface that acts as a negative electrode; a positive copper electrode is separated from the nanotube by a vacuum gap. A voltage applied to the electrodes causes a current to flow through the nanotube, turning the radio on. Changing the voltage also changes the vibrational rate of the nanotube, tuning it to a different frequency.

Next steps: The researchers are looking to integrate the radio into biological systems.